Retifanlimab regimen improves outcomes in advanced anal cancer
Click Here to Manage Email Alerts
Key takeaways:
- The addition of retifanlimab to chemotherapy conferred a 2-month improvement in PFS.
- Researchers reported a trend toward improved OS with the combination.
The addition of retifanlimab to standard first-line chemotherapy improved outcomes for certain patients with advanced squamous cell carcinoma of the anal canal, according to randomized phase 3 study results presented at ESMO Congress.
The regimen conferred a nearly 2-month improvement in PFS and a 6-month improvement in OS for patients with recurrent or metastatic disease who had not received prior systemic chemotherapy.
The findings suggest the combination could be a new standard of care for this population, Sheela Rao, MBBS, MD, FRCP, consultant medical oncologist at Royal Marsden Hospital NHS Foundation Trust in the U.K., and colleagues concluded.
A high percentage of patients with inoperable locally recurrent or metastatic squamous cell carcinoma of the anal canal respond to platinum-based chemotherapy; however, survival outcomes are suboptimal, according to study background.
Retifanlimab (Zynyz, Incyte) — an anti-PD-1 monoclonal antibody — is approved in the United States for treatment of adults with metastatic or recurrent locally advanced Merkel cell carcinoma.
Prior studies showed the agent has anti-tumor activity among patients with advanced squamous carcinoma of the anal canal whose disease progressed on platinum-based chemotherapy.
Rao and colleagues conducted the POD1UM-303 trial to assess the addition of retifanlimab to standard chemotherapy for patients who had not received treatment for locally recurrent or metastatic disease.
The double-blind trial included 308 adults (median age, 62 years; range, 29-86; 72% women; 87% white). One-third (36%) had liver metastases and 4% were known to be HIV positive.
Researchers assigned patients 1:1 to six cycles of standard carboplatin-paclitaxel plus either placebo or 500 mg retifanlimab every 4 weeks for up to 1 year. Protocol allowed for crossover.
PFS per blinded independent central review served as the primary endpoint. Secondary endpoints included OS, objective response rate, disease control rate, duration of response, safety and pharmacokinetics.
The trial met its primary endpoint, with results showing a statistically significant improvement in PFS with retifanlimab (9.3 months vs. 7.39 months; HR = 0.63; 95% CI, 0.47-0.84).
OS data remained immature; however, researchers observed a trend toward improved median OS with retifanlimab (29.2 months vs. 23 months; HR = 0.7; 95% CI, 0.49-1.01).
Analysis of other secondary outcomes favored retifanlimab, including ORR (55.8% vs. 44.2%; P = .0129) and disease control rate (87% vs. 79.9%).
The addition of retifanlimab to chemotherapy appeared well tolerated, according to investigators. Researchers identified no new safety signals that disrupted or compromised chemotherapy administration.